The present invention relates to a cable reel having a flexible cable such as a flat cable utilized for electrical connection between a fixed member and a movable member, and more particularly to a cable reel suitable for use with a steering device for an automobile.
A cable reel includes a flat cable constructed under a wound condition with a plurality of turns. The flat cable is fixed at its one end to a fixed member, and is also fixed at the other end to a movable member. The flat cable extends from both ends to the outside of the cable reel. When the movable member is rotated, the flat cable is wound up around the movable member, or it is unwound from the movable member. Thus, the movable member is allowed to be rotated by a predetermined amount. For example, the cable reel is used in a steering device for an automobile.
The flat cable as mentioned above is required to follow the rotation of the movable member to change its diameter of winding. Therefore, if the flat cable were formed of a material having a low flexural rigidity, a torque of the movable member upon unwinding would not be reliably transmitted from the inner circumferential side of the flat cable to the outer circumferential side thereof, and the flat cable would be bent back at the wound portion. to cope with this, the flat cable is usually formed by laminating a plurality of conductors between a pair of flexible films having a relatively large flexural rigidity. However, when the flat cable is in a mid position of winding up and unwinding, it is permitted to move radially. Under the condition, when external vibration is applied to the cable reel, the cable reel collides with each other or it collides with the outer ring wall of the fixed member or the inner ring wall of the movable member, causing the generation of undue noise. Particularly in the case that the cable reel is used in the automobile, for example, wherein vibration tends to be applied, the above problem remarkably occurs.